2.4  Basics of Operation 

This section will walk you through getting your Gemini system set up and running for the 

first time.  The steps that we'll follow are: 

 Setting up for observing 

Rough Polar alignment 

Putting the telescope in Startup Position (positioning scope with the 

counterweight down and the OTA pointing north if in the northern hemisphere, or 

south if in the southern hemisphere).  

 Powering on 

Setting parameters (mount type, time/date/location, etc.) 

Aligning mount using alignment stars 

Using the mount 

2.4.1   Setting Up for Observing 

Once you've completed the Gemini installation and have connected all the cables, you 

are ready to set up for observing.  

Important

: As with any telescope mount, make sure 

your telescope is properly balanced in both RA and Dec. before continuing.  Do this with 

all lenses and accessories that you intend to use attached.  Refer to the instructions for 

your mount to help you with this. 

2.4.1.1  Rough Polar Alignment 

In order to function correctly, your mount must be approximately polar aligned.  This 

means lining up the mount's polar axis with the Earth's rotational axis.  You do this by 

pointing the mount's polar axis toward the celestial pole (north celestial pole in the 

northern hemisphere, and south celestial pole in the southern hemisphere).  For visual 

use, this alignment need only be within a few degrees since Gemini can compensate for a 

fair amount of misalignment in a GoTo operation (using the modeling parameters) and 

when tracking (using Closed Loop tracking). 

There are several methods that you can use to achieve rough polar alignment.  The 

simplest is to use a compass and place your mount so that the polar axis points north (or 

south in the southern hemisphere).  Be sure to account for the magnetic variance of your 

geographic area.  Then, using the latitude scale on your mount, change the elevation of 

the polar axis to match your latitude.  In most cases, you should now be well enough 

polar aligned for visual use. 

At night in the northern hemisphere, you can also sight along (or through) the mount's 

polar axis and adjust the elevation and azimuth of the mount until it is pointing at Polaris.  

You can also move the telescope to 90

 declination (so that it is parallel with the mount's 

polar axis) and again adjust the elevation and azimuth of the mount until Polaris is 

centered in the telescope. 

Gemini Users Manual 

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